Method of coating insulated wire and the like



Dec. 15, 1936. A T CANDY' JR 2,063,889

METHOD IO1 COATING INSULATED WIRE AND THE LIKE Filed May 14', 1934 y fH HH E Patented Dec. 15, 1936 ,METHoD oF coA'rING INSULATED WIRE AND THE um: i

Albert T. candy, Jr., oak Park, nl., assignmto Candy & Company, Inc., Chicago, Ill., a corporation of Illinois Application May 14, 1934, Serial No. '125,439

z claims.4 (ci. 17a-zei) This invention relates to a method of coating insulated wire or the like and more particularly to the manufacture of a flame repellent insulated wire for electrical circuits.

In my previous application, entitled Method of l Coating Insulated Wire orthe Like, Serial No. 702,868, filed December 18, 1933, there is described a method that includes the step of sat urating a fabric jacketed insulated wire with a flame repellent pitchy substance and while the pitchy layer is in a vplastic and/or sticky condition,

passing the coated wire through a bedv of a dry, pulverized mixture of a readily fusible pigmented mass to cause the pigmented material to adhere to the coated wire and form a pigmented layer thereover. According to the present invention, I propose to applythe flame; repellent substance directly to the rubber covered wire and then spin or otherwise form a fabric jacket directly over the llame repellent layer while the same is in either a cold, or a molten, sticky condition, and thereafter impregnate and coat the fabric jacket with a molten colored waxy material.

By directly applying the fabric jacket 'tothe pitchy, flame repellent layer in plastic or sticky condition, the jacket is more rmly anchored to the insulated wire and is less liable to slip thereon. Also, by applying the molten pigmented material directly to the fabric jacket, the pigmented material is caused to impregnate the jacket and to form a coating thereover rmly anchored tothe jacket. mented layer is not substantially changed or altered by the black color ofthe flame .repellent pitch, since the fabric jacket keeps the pitch from substantially mingling with the pigmented layer and coming to the surface thereof. Furthermore, the fabric jacket itself may-be colored and thus serve to mask the depth of blackness that is usually characteristic of the flame repellentpitchy material.. Consequently, a more effective and more distinctlyI colored wire may be obtainedby my present method. v v

It is therefore an important object of this invention to provide a method for coating insulated At the same time the color of the` pig-` wire that possesses these enumerated advantages over prior methods.

It is a further important object of this invention to provide a methody for coating insulated wire wherein a fabric jacket is Adirectly applied by spinning or otherwise to a pitch coated insulated wire, and a molten pigmented material of a waxy and/or flame repellent character is applied directly to the fabric jacket to impregnate and coat the same.

lOther and further important objects of this invention will become apparent from the following description and appended claims.

This invention (in a preferred form) is illustrated in the drawing and'hereinafter more fully described.

On the drawing: 5 I

Figure 1 is a diagrammatic view, partly in section, illustrating the steps of the method of my invention.

Figure 2 is a fragmentary elevational view of the coated insulated wire of my invention, with 10 the coatings broken away to show the different laminations.

Figure 3 is an enlarged sectional view takenv substantially on the line III-III of Fig. 2.

\ lAs shown on the drawing:

The reference numeral I0 indicates a vat or receptacle for containing a bath II of flame repellent material, which may be any of the various pitchy substances commonly used for saturating the fabric jacket of insulated Wire.' In the present 20 invention, however, the saturant of the bath Il is applied directly to the usual rubber covering of an insulatedwire instead of being applied to the fabric jacket.

A vperforated drum I2 is mounted horizontally 25 Withinthe vat I0 for rotation in the bath I I. The construction of the drum I2 is more specifically described in my application above referred to and therefore needs no detailed description here; A strand, of wire I3 having the usual rubber insula- 30 tion is adapted to be wrappedaround the drum 'I2 for'the requisite number of turns necessary to give the desired length of immersion time in the bath of saturant. This has been found to be about 25 seconds.

The drum I2 maybe suitably turned byv means of a chain I4 and sprockets I5 and I6 on the shaft I 'I of the drum I2 and on a stub shaft I8, l respectively, the, stub shaft I8 being mounted above the tank I0 and being provided with a 40 handle I9 for manual operation. This mechanism is used merely for the initial winding of the wire I3 around the drum and thereafter may be rendered inoperative by means of a clutch device (not shown) to leave the drum I2 free to re- 45 volve during the actual Acoating operation.

The receptacle I0 is provided with suitable p means for heating the saturantain the bath II to the temperature desired. Since, according to my method, the saturant is heated to a comparatively 50 high temperature, say betweenv350 and 400 F., it is, advantageous to use an electrical heating unit, as is illustrated at 20. By this means, the

rubber covered wire reduce its viscosity and cause it to adhere to the the wire I3. Any excess of the saturant flows back into the bath Il.

The wire i3 next passes vertically upward through a braiding device, indicated generally at 22 and comprising any conventional type of device for braiding or spinning a fabric jacket about the wire I3. Said device 22 comprises, in general, a rotating head 23 carrying a plurality of bobbns 24 of the textile strands 25 from which the fabric jacket is to be formed. A fabric jacket may thus be applied directly over the coating of flame repellent material, while the material is still in a sticky and/or heated condition. My invention also contemplates the carrying out of the braiding step in a non-continuous manner from the saturating step, in which case the pitch coated insulated wire may be wound into reels after leaving the saturant bath II and then the wire used therefrom as desired and heated or not before being passed through the braiding device 22. A heating device is indicated at 36.

After leaving the braiding device 22, the wire I3 is reeled up before being passed through a bath of molten colored waxy material. It is not practical to carry these operations out in a continuous fashion, since the braiding operation is necessarily a rather slow one, whereas the wire may be passed through the colored wax bath at a comparatively high speed. Consequently, the wire is reeled between the braiding step and the step of applying colored wax thereto, during which interim the pitch layer has an opportunity to harden.

Said colored waxy material is contained within a vat or receptacle 26 identical with the vat I0. The equipment for effecting the immersion of the wire within the bath 2T of molten pigmented material is similar to the equipment already described in connection with the saturant bath II. After leaving the bath 21, the wire passes through a wiping device 28, which may be similar to the wiping device 2 I, and thence to a reel 29 on which the coated insulated wire is wound.

In Fig. l the gap in the schematic showing indicated at X represents a position at which various other operations may be performed. For instance, a nal coating of colored or colorless wax may be applied to the coated wire by means of spray -nozzles or otherwise to impart a slick finish to the coated insulated wire. Also, the coated wire may be passed through a tempering bath of water before being wound up on the reel. These steps are illustrated in my copending application above referred to and are optional in this invention.

The finished wire, as illustrated in Figs. 2 and 3,

comprises the conductor proper 30, which may be' either a single metal wire or a bundle of wire strands, a rubber sheath 3l surrounding the wire 30, a layer of flame repellent material 32 directly overlying the rubber sheath 3l, a fabric jacket 33, a pigmented layer 34 impregnating and coating said fabric jacket 33 and a final layer of colored or colorless wax 35 to impart a slick finish to the wire. As previously stated, the final layer 35 may be omitted. Also, the layer 34 may be either a colored wax layer or a pigmented layer of wax.

I3 and form a uniform,

The composition of the bath II may suitably be prepared by blending stearin pitch with various waxes, resins or gums in such proportions as to give a saturant having the desired melting point and having ame repellent properties. Various vegetable and animal pitches may be used, but stearin pitch has been found to be most suitable because of its excellent flame repellent property. Waxes, such as paraffin wax, Montan wax, petrolatum, canaubawax and the like, and gums or resins, such as coumarone and indene resins may be admixed with the pitch, Also, if desired, various fillers or inorganic substances of a non-combustible nature may be added to the saturating pitch.

In preparing the molten mixture of pigment and binder, various pitches, waxes, or mixtures of the two may be employed. The composition of the pigmented mixture may be varied also depending upon the particular pigment that is employed, although in general the mixture will contain as much pigment as can be satisfactorily carried by the molten mixture without rendering it too viscous. Examples of suitable types of pigments are iron oxides for producing browns and reds, chrome oxides for yellows and greens, titanium oxides and barium or calcium sulphates for producing whites and grays, and carbon black for producing blacks.

In place of insoluble pigments, various oil soluble dyes and coloring matters may be employed.

It will thus be apparent that the main steps of my process are, rst, the coating of the rubber covered wire with a flame repellent pitch, secondly, applying a fabric jacket directly to the pitch coated wire and, thirdly, impregnating and coating the fabric jacket with a colored material. This colored material may be either colored wax or a colored mixture of pigments, fillers, resins and/or gums and wax. Optionally, also, my process includes a nal step of applying either a clear or colored wax film to the coated wire to impart a slick nish thereto. At the time of applying the fabric jacket to the wire, the layer of flame repellent material is preferably in a heated condition, although this is not necessary.

It is an important feature of my invention that the flame repellent material first applied to the rubber sheath or insulation of the wire does not sufciently penetrate outwardly through the fabric jacket to form an appreciable layer over the fabric jacket. Rather instead, the flame repellent material constitutes a layer lying mainly beneath the fabric jacket and only penetrating the same as necessarily results from capillary action and any excess of the material.

The colored wax layer is applied over the fabric jacket by passing the jacketed wire rapidly through a molten bath of the colored wax, which is thereby caused to penetrate into the fabric jacket and become firmly anchored and embedded therein, as well as to form a layer over the entire surface of the jacket. The time of immersion of the wire in the molten wax bath is not such as will cause the underlying pitch layer t0 fiow outwardly through the jacket and commingle substantially with the colored wax layer. Consequently, if a colored fabric jacket is used, the jacket itself effectively masks the black color of the flame repellent layer underneath the jacket and the overlying colored wax layer then gives to the coated wire its own clear and distinct coloration. There is, of course, some slight intermingling of the particles of the colored wax layer with the black saturant or layer of flame 75 repellent material applied beneath the fabric jacket, but this intermingling is not sufficient to bring particles of the saturant or flame repellent material to the surface of the colored wax layer.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. In the method of making a coated insulated conductor having successively a layer of rubber over the conductor, a ame repellent pitch layer directly overlying said rubber, a textile fabric jacket over said pitch layer and a, final slick finish wax coating directly overlying said fabric jacket,

form a layer on the outside thereof, and directly applying to said jacket said wax coating at a temperature sufficiently low to prevent said wax from substantially commingling with said underlying pitch layer.

2. In the method of making a coated insulated conductor having successively a layer of rubber over the conductor, a ame repellent pitch layer directly overlying said rubber, a fabric jacket over said pitch layer and a colored Wax-like coating directly overlying said fabric jacket, the steps of braiding said fabric jacket over said pitch layer while the pitch is in a suiciently softened and sticky condition to cause said jacket to become embedded in said pitch layer but said pitch being sufficiently viscous not to penetrate completely through said jacket to form a layer on the outside thereof, and applying to said fabric jacket said colored Wax-like coating at a temperature sufliciently low to prevent said wax-like coating from substantially commingling with said underlying pitch layer.

ALBERT T. CANDY, JR. 

